J/? production in PHENIX

1
J/? production inPHENIX

• Raphaël Granier de Cassagnac
• LLR École polytechnique / IN2P3
• For the PHENIX collaboration
• Hot Quarks 2006
• Villasinius, Sardinia, May 20th

2
J/? in nucleus-nucleus(phenix preliminary QM05)
3
RAA versus Ncoll
Hugo Pereira da Costa, for PHENIX, QM05,
nucl-ex/0510051
4
Quick comparison to NA50

• Same magnitude
• 30 survival prob.
• No fundamental reason
• Differences
• Higher energy density
• (x10 beam energies)
• Balance between cold hot nuclear effects ?

5
J/? in deuteron-goldPRL96 (2006) 012304
6
Cold nuclear matter effects

• Various cold effects
• Shadowing or anti-shadowing
• (gluon saturation, Color Glass Condensate)
• Energy loss of initial parton
• pT broadening (Cronin effect)
• J/? (or cc ) absorption
• Something else ?

7
Deuteron ? ? Gold

• In PHENIX, J/? mostly produced by gluon fusion,
  and thus sensitive to gluon pdf
• Three rapidity ranges probe different momentum
  fraction of Au partons
• South (y lt -1.2) large x2 (in gold) 0.090
• Central (y 0) intermediate x2 0.020
• North (y gt 1.2) small x2 (in gold) 0.003

d
Au
8
RdAu versus rapidity
RdA

• Data favours
• (weak) shadowing
• Eskola, Kolhinen, Salgado
• prescription matches better
• (weak) absorption
• sabs 1 to 3 mb
• (4.18 0.35 mb _at_SPS)
• But with limited statistics difficult to
  disentangle nuclear effects !

• PHENIX, PRL96 (2006) 012304
• Klein,Vogt, PRL91 (2003) 142301
• Kopeliovich, NPA696 (2001) 669

9
RdAu versus Ncoll
RdA
High x2 0.09

• Black lines
• EKS98 from 0 to 3 mb
• Colored lines
• FGS for 3 mb
• Slopes consistent with shadowing models
• Especially low x2

Low x2 0.003
10
Cold nuclear matter effects

• Shadowing nuclear absorption (crucial !)

-0.35 lt y lt 0.35
1.2 lt y lt 2.2
PHENIX, QM05, nucl-ex/0510051 Vogt,
nucl-th/0507027
Error bar code bars statistical, bracket
systematic, box global.
11
NA50 only effects

• Cold effects
• Comovers (hadrons/partons?)
• Kinetic model (J/? ? c c )
• Thermal plasma
• All overestimate suppression !
• So does parton percolation
• Onset at Npart 90
• Simultaneous J/? ?c ?

(AuAu only)

• Capella, Ferreiro, EPJC42 (2005) 419
• Grandchamp et al, PRL92 (2004) 212301
• Kotstyuk et al, PRC68 (2003) 041902
• Digal, Fortuno, Satz, EPJC32 (2004) 547
• Private communications

12
RHIC new effects

• 1st. Variety of recombination coalescence
  models
• c c ? J/? (at freeze-out)
• goes as Ncc2 (poorly known)
• (other models not displayed)
• 2nd. One detailed QGP hydro J/? transport (Zhu
  et al)
• (here without cold nuclear effects, see later)
• Look at y, pT

(AuAu only)

• Grandchamp et al, PRL92 (2004) 212301
• Bratkoskaya et al, PRC69 (2004) 054903
• Andronic et al, PLB571 (2003) 36
• Zhu, Zhuang, Xu, PLB607 (2005) 107
• Private communications

13
y shape (vs recombination)

• Recombination emphasizes quark y-distribution
• Quark (open charm) y-distribution unknown
  
• No significant change in rapidity in data

Recombined only !
? Thews Mangano, PRC73 (2006) 014904c
14
ltpT2gt (vs Cronin effect)

• ltpT2gtAA ltpT2gtpp ? ? ?pT2 x L nuclear matter
  thickness
• (random walk of initial gluons)
• ? ? ?pT2 from pp and dA ?
• L lt-gt Ncoll conversion
• Negligible broadening _at_ y0 !?...
• (open symbols)

pp dAu AuAu
(lower energy survey)
Open symbol y 0 Full Curve y 2
ltpT2gt 2.51 0.32 L
VN Tram, Moriond 2006 PhD thesis
15
2nd. Zhu et al (updated)
(dominated by Cronin determined on dA data)
Predicted RAA (y0) (y2)

• Nuclear absorption (1 or 3 mb)
• Cronin effect from our dAu

Zhu, Zhuang, Xu, PLB607 (2005) 107 private
communication
16
3rd (simple) explanation

• Amount of anomalous suppression depends on cold
  nuclear effects amplitude
• But could as low as 30 to 40
• Compatible to feed-down ratio
• J/? 0.6 J/? 0.3 ?c 0.1 ?
• Recent lattice Td? 1.5 - 2.5 Tc
• e x (TdJ/? 2Tc)4 2 ec? edJ/? 32 ec !
• Wait for LHC ?

17
Conclusions (1)

• For now, 3 models to explain the data
• 1st Recombination ?
• But no sign of y or pT2 modifications
• J/? ? (Ncc)2 (but how much is Ncc ?)
• 2nd J/? detailed transport in hydro QGP
• 3rd Sequential melting ?
• J/? may still survive _at_ RHIC
• All assume a QGP

18
Conclusions (2)

• What do we need to answer ?
• Final AA analysis
• A bit more data more bins !
• With a better pp ref (run 5)
• With J/? elliptic flow ? ?
• More dA ! Better handle cold nuclear effects
• More AA ! With open charm, ?,
• First look at ? and upsilons
• Going on with run 5 pp
• Better open charm measurements
• Si VTX upgrade ?
• LHC !

Zhu, Zhuang, Xu, PLB607 (2005) 107
19
13 Countries 62 Institutions 550
Participants
as of March 2005
20
Back up slides
21
Quick look at NA60

• In In-In collisions, preliminary plateau also
  rules out percolation, comovers and available
  plasma

Roberta Arnaldi, QM05

• Percolation
• Plasma
• Comovers

NA60 preliminary
22
3rd Sequential melting

• Sequential melting
• J/? survival only
• Cold nuclear matter effects derived from dAu data
  for RHIC
• Axis cannot be energy density since same ?0
  (1fm/c) is assume for SPS and RHIC !
• Larger at SPS
• Smaller at RHIC

Karsch, Kharzeev Satz hep-ph/0512239
23
Quick look to open charm

• Through semileptonic decays (D ? e)

25 systematic uncertainties (without Silicon
vertex detector upgrade)
PHENIX, PRL94 (2005) 082301
24
Charm quench flow
25
Na50/Phenix comparisons
PHENIX expected
PHENIX expected
1mb
1mb
NA50 expected 4.18mb
NA50 expected 4.18 mb
3mb
3mb
Consistent suppression amplitude observed but
cold nuclear effects may be different
26
measured/expected vs ?Bj
(x ?0) !
?abs 3 mb
?abs 1 mb
Below unity ! Suppression amplitude consistent
within error bars
27
measured/expected vs Npart
?abs 3 mb
?abs 1 mb
Under unity Larger difference when 1mb but
compatible within error bars
28
recombination/suppression
29
pT spectra

• In pp
• ltpT2gt 2.5 GeV 2
• In AuAu CuCu
• ltpT2gt 3 ? 5.3 GeV 2

AuAu (y?1.2,2.2)
30
ltpT2gt (vs recombination)
Robert Thews, SQM06
31
ltpT2gt (vs recombination)
AuAu
CuCu
100 pQCD kT
100 recombined
Lines from Thews Mangano, PRC73 (2006) 014904

• Seems to favor recombination scenario
• But Cronin effect not under control

32
Cronin effect
Scattering of initial gluons of nucleon before
ccbar formation random walk ltpt2gtAA ltpt2gtpp
???(ltpt2gt) LAA

v s 17.3 GeV NA50/60 PbPb, InIn v s 19.4
GeV NA3 pp, NA38 pCu, pU,OU, SU v s
27.4 GeV NA50 pBe, pAl, pCu, pW v s 29.1
GeV NA51 pp, pd, NA50 pAl, pW v s 38.8
GeV E866/789/771

• nuclear density, ? elastic gluon-nucleon
  scattering cross section, ?(ltpt2gt)
• kick given by each scattering and L average
  thickness of nuclear matter

33
Cronin effect
Cronin ltpt2gtAA ltpt2gtpp ???(ltpt2gt) LAA

Extrapolation curve from PHENIX J/? results in
pp and dAu
34
Cronin effect
Cronin ltpt2gtAA ltpt2gtpp ???(ltpt2gt)
LAA Extrapolation curve from PHENIX J/? results
in pp and dAu

pp dAu AuAu
At forward rapidity, ltpt2gt variation compatible
with this Cronin extrapolation At mid rapidity,
measurements in pp and dAu indicate a weak
Cronin effect
35
A busy plot about ltpT2gt

• ( curves to be compared with AA _at_ 1.2ltylt2.2 )

36
Rapidity width
Width pp 1.75 ? 0.21
No noticeable change in rapidity width
VN Tram thesis
37
More on transport model

• 21D hydro
• Boltzman-type transport
• Local equilibrium
• (0.8 0.6 fm/c)
• Normal to anomalous
• Tc 165 MeV
• Tfo 60 MeV
• g? ? cc
• 40 feeddown
• No in-medium mod.
• No absorption _at_RHIC (here)

Zhu, Zhuang, Xu, PLB607 (2005) 107
38
How does PHENIX see the J/? ?

• J/? ? ee identified in RICH and EMCal
• ? lt 0.35
• pe gt 0.2 GeV
• J/? ? µµ
• identified in 2 fwd spectrometers
• 1.2 lt ? lt 2.4
• pµ gt 2 GeV
• Centrality and vertex given by
• BBC in 3lt?lt3.9
• and ZDC

39
J/? in PHENIX
1 PRL92 (2004) 051802 2 PRC69 (2004)
014901 3 PRL96 (2006) 012304 4 QM05,
nucl-ex/0510051
Year Ions ?sNN Luminosity Status J/? (ee µµ)
2000 Au-Au 130 GeV 1 ?b-1 Central (electrons) 0
2001 Au-Au 200 GeV 24 ?b-1 Central 13 0 1
2002 p-p 200 GeV 0.15 pb-1 1 muon arm 46 66 2
2002 d-Au 200 GeV 2.74 nb-1 Central 360 1660 3
2003 p-p 200 GeV 0.35 pb-1 2 muon arms 130 450 3
Au-Au 200 GeV 240 ?b-1 preliminary 1000 5000 4
2004 Au-Au 63 GeV 9.1 ?b-1 analysis 13
p-p 200 GeV 324 nb-1
Cu-Cu 200 GeV 4.8 nb-1 preliminary 1000 10000 4
2005 Cu-Cu 63 GeV 190 mb-1 analysis 10 200
p-p 200 GeV 3.8 pb-1 1500 10000
2006 p-p 200 GeV ?? Running ??
40
First upsilons

• Run 5 pp (3 pb-1)

Hie Wei, Quark Matter 2005
41
Centrality analysis

• Au breaks up in our south beam counter
• Define 4 centrality classes
• Relate centrality to ltNcollgt
• through Glauber computation
• ltNcollgt 8.4 0.7

ltNcollgt 3.2 0.3
Counts
Peripheral
ltNcollgt 15.0 1.0
Central
MB
South BBC Charge
42
Centrality analysis

• BBC charge versus ZDC energy

Most central 0 - 5 lt Npart gt 351 2.9 lt
Ncoll gt 1065 105
Most peripheral 80 92.2 lt Npart gt 6.3
1.2 lt Ncoll gt 4.9 1.2
43
Cross section versus pT
?ltpT2gt ltpT2gtdAu ltpT2gtpp Backward 1.77
0.37 GeV 2 Mid (-1.28 0.94 GeV 2 ) Forward
1.12 0.35 GeV 2
PHENIX, PRL96 (2006) 012304

• Some pT broadening

44
RdAu versus pT
RdA
High x2
Low x2

• Broadening comparable to lower energy (?s
  39 GeV in E866)

45
dAu perspectives

• We have seen small nuclear effects !
• Weak shadowing / antishadowing
• Weak absorption ( 1 to 3 mb)
• pT broadening similar to lower energies
• Difficult to disentangle given statistics
• Need more luminosity !
• But, no large nuclear effect !
• Good news to see J/? suppression in Au-Au !

46
J/? in proton-proton
47
Cross section vs rapidity

• Total cross section
• ? (pp ? J/?)
• 2.61 0.20 0.26 µb
• Error from fit (incl. syst and stat)
• Error on absolute normalization

PHENIX, PRL96 (2006) 012304
48
Cross section versus pT

• Fit the function
• ltpT2gt 2.51 0.21
• ( GeV2 )

PHENIX, PRL96 (2006) 012304
49
pp perspectives

• Production mechanism
• Color Octet Model does the job
• In AA (or dA)
• Large combinatorial background
• Low physics background
• (Drell-Yan or dileptons from open charm)
• pp is our baseline
• Nuclear modification factor
• Run5 pp analysis going on
• gt 10 times statistics

PRL96, 012304 (2006)
50
NA50 versus NA60 (QM05)
No overlap
Good agreement !
51
Dielectron pp and dA
52
? versus X compared to lower ?s

• E866, PRL 84, (2000) 3256 NA3, ZP C20, (1983)
  101
• PHENIX, PRL96 (2006) 012304

XF Xd - XAu
X2 (in gold)

• Not universal versus X2 shadowing is not the
  whole story.
• Same versus XF for diff ?s. Incident parton
  energy loss ? (high Xd high XF)
• Energy loss expected to be weak at RHIC energy.

53
How to get xF scaling ?
54
J/? transverse momentum (run2)
Color Singlet Model Color Octet Model (from
Nayak et al. hep/ph 0302095) COM contribution
is dominant, as for high pT J/? _at_ Tevatron

• Phenomenological exponential fits of dimuon and
  dielectron data give mean pT
• ltpTgt 1.80 0.23 (stat) 0.16 (sys) GeV/c

55
J/? cross section from run 2
Results consistent with shapes from various
models and PDF. Take the PYTHIA shape to
extract our cross-section
??
ee
Error from absolute normalization

• Integrated cross-section
• RUN2 234 36 (stat) 34 (sys) 24(abs) µb
• RUN3 159 nb 8.5 (fit) 12.3 (abs)

Consistent (1.3 sigma difference)
56
Naive picture

• Less absorption
• Shadowing
• Energy loss

(Kopeliovich)
57
Tuchin Kharzeev

• Hard probes 2004
• hep-ph/0504133
• Coherent production of charm (open or closed)
• (ylt0 production time to low to make computation)
• Shadowing from CGC computation

58
Tuchin Kharzeev

• absorption for
• SPS fermilab

59
goldgold extrapolation